sumers receive medicines whose ingredients are still active. That’s far more important.”

He speaks from his own past experience as the father of an allergic child. To such chil-dren, an adrenaline syringe can be a lifesaver if they experience anaphylactic shock.

Adrenaline is an example of a medicine that must be stored at the correct temperature. It loses its effect if it is exposed to cold. The same happens to other medicines at other temperatures.

“For example, the temperature might exceed the maximum permitted limit for part of a 24-hour period,” Niclas explains.

Simple procedure, SophiSticated technology

Despite its small size, the data logger is very sophisticated. It works on two levels. First, it is programmed with all the conditions required for the product in question. Then, when the shipment reaches its destination, the data logger is read with a simple handheld device. A green light indicates that all the conditions have been met but a red light indicates that limits have been exceeded. In the latter case,

calibrated data logging keeps medicines effective until they reach the customer

Temperature is crucially important not only during the production of pharmaceutical products but also during their transport and storage. “An adrenaline syringe can become ineffective if it gets too cold in transit,” ex-plains Niclas Ohlsson, CEO of Temperature Sensitive Solutions AB (TSS).

TSS specialises in measuring and logging the temperature throughout the entire transport chain for pharmaceutical products. The com-pany’s method is based on a systems approach, advanced software solutions and traceable calibrated data loggers which accompany a shipment throughout its journey. The tiny logger is about the size of a large button.The process is governed by an extensive body of regulations, strict legislation, and powerful regulatory authorities such as the American Food and Drug Administration (FDA).

Saving liveSTo Niclas Ohlsson, though, there is an even more compelling reason for his work than mere regulatory compliance:

“Our job is to ensure that individual con-

“We ask Pentronic to calibrate each individual data logger, even though the regulations do not require it,” says Niclas Ohlsson, CEO of TSS, shown here in the laboratory with a tray of newly calibrated data loggers.

pentronic Scandinavia’s largest manufacturer of industrial temperature sensors vol. 2 no. 6 2009

all the logged data are transferred into a com-puter to be analysed by experts before the product is permitted to continue its journey.

“We’re now launching online software, which means that the customer can do this analysis anywhere without needing direct access to the software,” Niclas says.

The company offers a complete solution which also includes special packaging. The loggers are supplied by subcontractors. Each individual logger is calibrated by Pentronic’s accredited calibration laboratory, which is a reliable way to ensure the device’s readings are correct.

“We choose to calibrate every single logger, even though the regulations permit random sampling,” Niclas says. “That’s because we focus on the health of individual users and not just on complying with the regulations.”

Began with ice hockey This highly developed goal-oriented approach can be traced back to the personal back-ground of the company’s owner and founder, Mikael Thelvén. Now Chairman of the Board of TSS, in his youth he was a successful ice hockey player with the elite Djurgården team in Sweden and a member of Sweden’s national team Tre Kronor. He also spent five seasons in the NHL playing for the Boston Bruins.

Upon retiring from hockey in 1991, Thelvén founded TSS as an agency selling solutions developed by another company. That supplier could not meet his high require-ments, so instead he developed his own technology in collaboration with his custom-ers. The result is a company that is one of the leaders in its field.

The data logger, which records the shipment temperature of medicines, is very small.

The Technical manager’S TaSk:

make something good even better How can you improve on something that already works well? That’s the challenge for Pentronic’s new technical manager, Lars Björkvik.

Lars Björkvik is a well-known figure within the industrial sector in the Swedish town of Västervik, located a few kilometres from Pentronic’s headquarters. Lars graduated in engineering from the nearby Linköping University, where he specialised in mechani-cal and design engineering. He then taught solid mechanics at the university before joining Electrolux’s vacuum cleaner factory in Västervik as a design engineer. He advanced to become head of development and then factory manager before choosing to leave the company in 2002.

“I’ve always been interesting in education, so I began teaching at an upper secondary school while also starting a postgraduate research degree at Linköping University,” he explains.

integrate more His research was put on hold in 2004, when he was appointed as the CEO of the mu-

joined Pentronic. The position of technical manager has been newly created and has a clear purpose:

“My job is to expand Pentronic’s produc-tion by such measures as further integrating our development and production operations,” Lars says.

perSonal reSponSiBilityWhat impression of Pentronic has Lars gained from his first few weeks on the job?“The company is very well organised and production works well. With 99% delivery reliability calculated on a daily basis, em-ployees appear to be taking a lot of personal responsibility to ensure both quality and de-liveries,” he says.

Most of his experience of large-scale production comes from Electrolux, which was one of the first to introduce the concept of lean production. The company he has now joined must be highly responsive to its customers’ demands and be able to quickly adapt its products and manufacturing processes to those demands.

“Of course Pentronic’s operations will never be highly automated but it is still pos-sible to apply lessons learned from large-scale manufacturing,” he says. “The primary chal-lenge is to apply continual improvements in order to increase productivity.”

“Softer” values are playing more and more of a key role in temperature sensors.

“It’s no longer unusual for us to invest more work time in testing and documenting a sensor than in actually making it,” explains Margareta Forsberg, sales engineer with Pentronic.

This trend has been driven by increasing de-mands for proven measurement performance and other properties that must be documented in various ways.

A lot of expertise and testing is already incorporated into every Pentronic sensor. For example, most sensors undergo a trace-able final inspection and are equipped with

the resulting cer t i f i ca te . These meas-ures increase value for the customer but also require resources.

cuStomer demandS

As well as these stand-ardised proc-edures, Pen-tronic also prov ides a

“Softer” values increasingly important to temperature sensors

whole range of additional measures accord-ing to the customer’s wishes. Margareta Forsberg gives some examples:

“They could be material certificates, pressure tests, license welding, drop tests, documented electropolishing, sheath integrity tests (testing welds and materials for leakage) and accredited calibration.”

Some tests are customer specific while others are included in Pentronic’s regular range of services. The latter includes the certification of sensors in accordance with requirements specified by classification societies, government agencies, industry associations, and similar bodies.

Jonny Heimler is in charge of the certification of temperature sensors. He displays a list of the certificates which Pentronic currently holds.

“Our sensor designs are approved in three areas: to meet hygienic standards, to comply with import regulations for certain countries, and for maritime shipping,” he explains.

claSSified SenSorS Within the field of maritime shipping alone, Pentronic maintains classifications with seven classification societies, which are a type of insurance company. In the field of hygiene, that is, food and pharmaceuticals, the com-pany has sensors certified in accordance with 3A for the United States, EHEDG for Europe, and the Sanitary Certificate for Russia. Import

nicipality business development company, Västervik Framåt. It was a turbulent time because Electrolux was closing its factory in the town. The closure brought a number of key employees to Pentronic.

Lars then became the site manager of the Västervik-based factory of Gunnebo Fastening, a leading supplier of fastening products such as nails and screws to the European market. From there, Lars has now

regulations include Pattern Approval Russia, which is at a level above GOST.

Classifying or certifying a single sensor type can cost up to a five-figure sum in euros plus subsequent annual fees to maintain the certification. Other requirements that are be-coming increasingly common are a certificate of the sensor’s material composition in accord-ance with EN 10204-3.1b and a corresponding certificate for measurement readings.

More stringent requirements naturally also increase the cost of a sensor, but they also increase its value to the customer and reduce costs at the next stage of the chain. In some cases, testing and documentation are a requirement before a temperature sensor is permitted to be used at all.

Lars Björkvik, new technical manager at Pentronic.

Jonny Heimler displays various certificates.

To express viewpoints or ask questions, contact Professor Dan Loyd, Linköping University

by e-mail to: dan.loyd@liu.se

Straight from the laB

does coffee stay hotter in a white or black mug? Christmas is traditionally a holiday that places a lot of importance on food and drink. We have therefore chosen to include an article on this subject in our December issue of Pentronic News. Professor Dan Loyd answers the following question:

QUESTION: Does coffee cool faster in a black mug than in a white one? Mai-Gret F.

ANSWER: The colour of the mug only affects that portion of the heat flow which radiates from the outer surface of the mug to its surround-ings. Inside the mug, the heat is transferred via natural convection from the hot coffee to the mug’s inner surface, and then via heat conduction through the wall of the mug to its outer surface. On the outer surface, in addition to the heat flow that radiates outwards, there is also a convective heat transfer to the mug’s surroundings. The heat flow from the bottom of the mug to the table is primarily via conduction. The heat transfer from the surface of the coffee to the surroundings occurs largely via natural convection and radiation. The coffee surface also gives off steam. This phase change of water to steam requires heat, which results in additional cooling of the coffee.

very little differenceThe radiation from the mug’s outer surface is influenced by factors like the surface’s tem-perature and emissions coefficient. The latter depends on the materials used to make the mug, the surface structure, et cetera. A black mug has a slightly higher emissions coefficient than a white one in the wave range relevant to thermal radiation, but the difference is not large. A black mug therefore cools slightly faster than

a white one, but in most cases the difference in the cooling speed is tiny. The diagram shows an experiment involving a black mug and a white one. We can see that in this experiment, the difference between the cooling time for coffee in a white mug compared to a black mug is basically nonexistent. If the mug is covered, for instance with a saucer, this will reduce the effect of the surface vaporisation (see diagram). In this case, too, the difference in cooling time between the black mug and the white one is basically nonexistent.

like a temperature SenSorIn thermal terms, a sensor closely resembles a coffee mug. When installing a sensor, it is therefore essential always to check what effect the radiation process can have on the heat flow and therefore on the temperature measurement process. The temperature of a wet sensor will be affected by the vapourisation process, which requires heat. In both cases, the temperature readings will therefore be affected.

QueStionS? anSwerS !

Pentronic’s laboratory is accredited since 1988

more process sensors in the labThe trend at Pentronic’s accredited labora-tory is clear: while the number of reference sensors coming in for calibration remains constant, the number of process sensors is increasing significantly.

“Customers want to reduce their poten-tial sources of error by using traceably cali-brated sensors within their actual processes,” explains lab manager Lars Grönlund.

Machinery builders, who buy sensors from Pentronic and install them as com-ponents in equipment for end customers, are also increasingly ordering traceably calibrated sensors.Behind this shift are demands for improved

quality, measurement performance and documentation. Instead of expanding their own calibration operations, more and more companies are choosing to outsource the work to accredited calibration laboratories.

Lars says another explanation is that the first wave of baby boomers is now retiring. Calibration is seldom a full-time job, so instead of training replacement calibrators, companies are outsourcing the function and focusing their own efforts on implementing internal control measures.

“Another type of situation occurs when Pentronic supplies a set of sensors, all of which are traceably calibrated,” he says. “When re-

newed calibration is required, the customer sends some of the sensors to us, and they are regarded as being representative of the whole set.”

This trend has also led to an increased demand for rapid delivery times. Previously, the customer would accept the lack of a reference sensor for several weeks. Now, the sensors must be calibrated and returned within a week or so – and sometimes even within a few days. This faster turnaround time re-quires even more efficient routines at the lab. Another result is that the number of on-site calibrations done at the customer’s premises is increasing.

total business offering determines performance Today, customers demand proven perform-ance. Blind faith in decimal places has faded away and it’s taken for granted that temperature sensors come with traceable calibration.

Suppliers of calibration equipment must there-fore fine tune their total business offerings so that customers can achieve even more precise and reliable measurement results.

This total offering embraces not only the newly produced sensors but also the calibration process, instrument performance, and cor-rect installation of the equipment. As well, all the components must be designed to work together, to function within a specific environ-ment, and of course to perform the required measurement task.

On top of all this there is the human factor. Everyone who installs, checks and uses the

equipment must know their job both in theory and in practice.

Pentronic has one of Europe’s leading accredited calibration laboratories. The com-pany’s product portfolio also includes every-thing from connection cables and indicators to calibration baths and measuring bridges. For the past two decades Pentronic has also offered regular training courses, also in English and abroad. A number of companies in Sweden regularly send their new employees whose duties include working with temperature to take courses with Pentronic. All these factors make Pentronic a total supplier within the field of temperature.

SE-590 93 Gunnebo, SwedenFax. +46 490 237 66, Tel. +46 490 25 85 00

info@pentronic.se, www.pentronic.se

Temperature sensorsConnectors and cablesTemperature transmittersIR-pyrometersTemperature indicatorsTemperature controllers

DataloggersTemperature calibration equipmentTemperature calibration servicesTraining courses in temperatureMoisture and thickness monitorsFlowmeters

pentronic’s products and services

Opinions and questions are welcome at:hans.wenegard@pentronic.se

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what can a calibration certificate tell you?What should I do when the correction terms on the certificate are for temperatures that aren’t the ones I want to use? What me-asurement uncertainty is associated with interpolations? What about extrapolating? Many questions arise when calculating measurement uncertainty and interpreting calibration certificates.

with the closest calibrated point. If there are several calibrated points with varying ΔT, this recalculation should be done to a higher percentage as you deem appropriate. Nor-mally, thermocouples exhibit significantly greater variation between their extreme values than Pt100 sensors do.

One basic rule is never to extrapo-late to values that lie outside the highest and lowest calibration temperatures. If you cannot predict exactly how your

measurement equipment will be used, it can be wise to request the calibration of a few extra equidistant temperature points. This can be a useful procedure

for your company’s secondary reference thermometers.

Because the rule is to round off measu-rement uncertainty upwards in accordance with the test device’s resolution, measurement uncertainty often has relatively large margins. For example, 0.3123 is rounded up to 0.4 at a resolution of 0.1 of a degree. An exception to this rule says that if the value exceeds the decimal of resolution by less than 5% (here: 0.05 x 0.1), you can round down. In this case, that would mean that uncertainty figures up to 0.305 should be rounded down to 0.3. If the result is to be used immediately in a subsequent calibration, no rounding off is necessary. For a more complete understan-ding of estimating measurement uncertainty and the traceability of calibration, consult the references given below or, even better, attend Pentronic’s courses.

[Ref 1] Pentronic News 09-3[Ref 2] Search EA-4/02 via Google

A calibration certificate which bears the SWEDAC logo, (or e.g. DKD, UKAS) the registration number of the laboratory, and a reference to the ISO/IEC 17025 standard indicates that a calibration has been done under accreditation (See Figure 1). This means that an independent third party is carefully monitoring the laboratory to ensure that it maintains its level of quality. This accreditation system will soon be accepted all over the industrial world.

BaSic informationThe contents and layout of the calibration certificate are largely governed by the ISO/IEC 17025 standard, but the certificate also contains additional information of use to customers. The certificate gives the date of calibration, which is important for ensuring that the stipulated calibration intervals are followed. There is also a short description of the device(s) being tested and the resolution of the indicating instrument. The condition of the test devices on arrival should also be noted, as this can indicate damage during shipment. It is particularly important to identify the test devices by their serial numbers or a similar type of individual labelling system. The calibration only applies to these individual devices and/or to the linkage between them. The certificate should also specify the calib ration work that was done and the temperature levels involved.

Specifying the calibration method, measurement environment, preparatory work

and equipment used is helpful to the client because this makes it possible to compare repeated calibrations done over a long period of time.

The results page of the certificate gives the correction terms (see Figure 2) at the various temperatures. The deviations are not precise. If there is sufficient resolution, repeated readings taken on the same equipment will show a spread in the values read both on the reference system and on the device being calibrated.[ref 1] The true value does not change; it is our inability to measure correctly which is at work. Uncertainties present in the entire calibration setup affect the result. After calculating in accordance with the stipulated standardised methods, [ref 2] we obtain a total measurement uncertainty which, with about 95% probability, will apply to all the measurement results. In other words, in principle we allow an even greater deviation in 5% of the measurement results. Because this calibration method is standardised, everyone measures in the same way and the measurement uncertainty – the indicator of quality – is therefore comparable. See Figure 2.

SuBSeQuent analySiS When you want to analyse deviation and measurement uncertainty in your own subsequent calibrations, sometimes the calibration certificate stipulates temperatures other than the ones you want to use. If, for example, the deviations stated on the calibration certificate are 0.4 at 500 °C and 0.8 at 600 °C and you want to know the deviation at 550 °C, you can do a linear interpolation and use 0.6 there. See Figure 3.

Of course, the best solution would be to do a new calibration at 550 °C. In this case, the uncertainty at the interpolated point should be recalculated upwards by 50% compared

Figure 2: A graphic representation of measurement error and measurement uncertainty. The measurement error can be corrected but the measurement uncertainty remains.

Figure 1: The SWEDAC logo at the top left of the calibration certificate indicates that the calibration has been done under accredita-tion. Other countries’ accredited calibration certificates are valid in Sweden and vice versa.

Figure 3. A deviation of ΔT at 500 and 600 °C can be used to linear interpolate a value, e.g. for 550 °C. Extrapolation outside the interval of 500-600 °C is not permitted. The measurement uncertainty (shown here as braces) increases as the distance of the interpolated (red) point from the (blue) calibration points increases.